1. Technical Field
The present disclosure relates to an antenna apparatus, and more particularly, relates to a small antenna apparatus operable in multiple bands. The present disclosure also relates to a communication apparatus and an electronic device, provided with such an antenna apparatus.
2. Description of Related Art
A multiband antenna of Japanese Patent Laid-open Publication No. 2010-010960 is provided with: at least two antenna elements for a low frequency band and for a high frequency band; a feed point portion shared between the two antenna elements for the low frequency band and for the high frequency band; and an impedance matching unit inserted and connected between a feed point end and an open end of the antenna element for the high frequency band. The impedance matching unit is composed of an LC parallel resonant circuit operable as an inductor in the low frequency band, and operable as a capacitor in the high frequency band.
A multiband antenna of Japanese Patent Laid-open Publication No. 2012-085215 is provided with: a substrate; a ground element formed on any surface of the substrate and having a ground voltage; a first antenna element formed on any surface of the substrate; a feed portion for feeding the first antenna element; a second antenna element formed on an opposite surface of the substrate to the surface on which the first antenna element is formed; a first ground wire extending from the ground element; a first interlayer connecting portion formed to penetrate through the substrate, and electrically connecting the first and second antenna elements; a first capacitive coupling portion where the first and second antenna elements are overlapped or close to each other via the substrate, thus capacitively coupling to each other; and a loop structure electrically configured by the first antenna element, the second antenna element, the first interlayer connecting portion, and the first capacitive coupling portion. Each of the first antenna element, the second antenna element, the ground element, and the first ground wire is formed by a conductive pattern on any surface of the substrate.